What Is Veterinary Diagnostic Imaging For Felines?
Veterinary diagnostic imaging includes radiographs (X-rays), ultrasound, MRIs, and CT scans, all of which are used as diagnostic tools to collect information about your cat's health. The vast majority of imaging is non-invasive and completely painless. However, some imaging may require sedation or even anesthesia because the cat must be kept still to allow for adequate images to be produced. Veterinarians use these images to collect information on your cat to help them to make a medical and sometimes surgical plan.
When Is Veterinary Diagnostic Imaging Necessary For Your Cat?
After your veterinarian has examined your cat, he or she may want to begin to collect more information that will lead to a diagnosis and a subsequent treatment plan. X-rays are usually the first line of imaging. The X-ray may lead to a diagnosis, which allows your veterinarian to move forward with a plan. However, sometimes the next step may be ultrasound to get a more thorough or specific look at a particular area of the cat's body.
For instance, if your cat is vomiting and feeling ill, your veterinarian may take an X-ray to look for possible causes, such as obstruction of the intestines or an obvious foreign body. The X-ray may show some signs of intestinal obstruction. However, before proceeding to surgery, it would be prudent in some cases to follow with an abdominal ultrasound. The ultrasound may provide more detail about the area and thus provide more confidence in the treatment plan to move forward with surgery. Occasionally, X-rays and ultrasounds allow for a definitive diagnosis, but other times they will simply add more information to help put the puzzle together to ensure the best treatment plan for your cat.
The four types of veterinary diagnostic imaging our veterinarians may utilize to assist in the diagnosis of your cat's condition are:
- X-Rays
- MRIs
- Ultrasounds
- CT Scans
More information on each of these types of radiographs is provided below.
Cat X-Rays
Cat X-rays have been in use throughout the medical community for many decades. They are by far the most regularly used form of diagnostic imaging in the veterinary industry because they are cost-effective (comparatively speaking), and they can accurately diagnose the state of skeletal structure and composition, large body cavities, and the presence of many foreign objects. Cat X-rays are painless, but some cats can benefit from sedation to reduce anxiety and stress.
Cat X-rays usually proceed as follows:
- The cat is placed on the X-ray table.
- A technician positions the X-ray machine so that the X-ray beam targets only the area of interest.
- Modern X-ray equipment allows for low levels of radiation and is thus perfectly safe for your cat when used occasionally.
- Because cat X-rays are static images, the procedure usually requires less time than a procedure like an MRI.
Cat X-rays have traditionally been captured on actual film, and they still can be when necessary. However, our X-ray images are now digital, which allows us to capture the images on a secure server that our veterinarians can access at any time and also share with specialists, if necessary.
Cat Ultrasounds
A cat ultrasound is the second most common type of diagnostic imaging tool veterinarians use to diagnose a cat's medical condition. Ultrasounds use soundwaves to examine and photograph internal tissues in real time. An ultrasound allows a veterinarian to see into a cat's body, allowing for easy viewing of organs from different angles, which is not easily achieved through X-rays.
A cat ultrasound usually proceeds as follows:
- A small probe that emits sound waves is pressed against the cat's skin and directed at specific areas of the cat's body.
- The sound waves are directed to various parts of the cat's abdominal area by manually shifting the probe's position.
- The sound beam changes velocity while passing through varying body tissue density, which causes echoes.
- The ultrasound equipment converts these echoes into electrical impulses, which are then further transformed into a digital image that represents the appearance of the tissues.
- These images are viewed by your veterinarian and can be emailed to a specialist for further review at any time.
In modern scanning systems like the ones Countryside Veterinary Clinic has on-site and uses on our feline patients, the sound beam sweeps through the body many times per second. This produces a dynamic, real-time image that changes as the cat ultrasound device moves across a cat's body. We can use the results of an ultrasound to help determine the most effective treatment protocol.
Common symptoms that may cause a veterinarian to use ultrasound include vomiting, weight loss, urinary bladder disease. intestinal blockage, pregnancy, fluid in the chest or abdomen, and heart disease.
Cat MRI
Magnetic resonance imaging, or MRI, is the newest form of diagnostic imaging being used for both human and veterinary medicine. Cat MRI equipment generates a very powerful magnetic field, resulting in detailed anatomic images of whatever part of a cat's body is being scanned. No X-rays are involved, and a cat MRI is considered extremely safe.
A cat MRI procedure usually proceeds as follows:
The cat's body is continuously pulsed with radio waves for a period of time, usually 10 - 20 minutes
- Cats must be sedated for this procedure because they cannot be restrained by humans and must remain still during the procedure.
- For the procedure, a cat is placed in a tubular electromagnetic chamber.
- The pulsing causes the cat's body tissues to emit radio frequency waves that can be detected by the MRI equipment. Many repetitions of these pulses and subsequent emissions are required in order to generate adequate digital feedback for the equipment to interpret.
- The feedback is then converted into images that can be displayed on a screen, and can also be saved for future study.
A cat MRI is not used as regularly as an X-ray or ultrasound because the equipment is very expensive, very large, and requires specially trained technicians to operate. We can refer your cat to a specialist with this capability if the need should arise.
CT Scans For cats
CT scans for cats, also known as "cat scans," are computer enhanced cat X-ray procedures most often used to evaluate complex parts of the body, such as the head, chest, some joints, and various internal organs. CT scans show different levels of tissue density and they produce more detailed images than X-rays. Unlike MRI's, CT scans for cats do not use magnetic field waves so they cannot compare changes in fluid levels due to inflammation or bleeding. Therefore, CT scans for cats are used in situations where an MRI is considered unnecessary but a traditional X-ray is inconclusive or insufficient.
CT scans for cats usually proceed as follows:
- Cats must be sedated for this procedure because they cannot be restrained by humans and must remain still during the procedure.
- The cat is placed on a motorized bed inside of a CT scanner, a machine that takes a series of X-rays from various angles.*
- When one series, or scan, is completed, the bed moves forward, and another scan is taken.
- A computer uses these scans to create cross-sectional images of the body part under investigation and then displays the images on a monitor (an X-ray dye may be injected intravenously to make it easier to see abnormalities.)
- By sequentially scanning an entire body area, an organ or other structure can be imaged without invasively penetrating the body or disrupting neighboring structures.
CT scans for cats are most often used by our veterinarians to detect structural changes deep within a cat's body, including:
- Tumors
- Deep abscesses or the presence of foreign bodies
- Fractures
Just like MRI equipment, CT scan equipment is very expensive, large and requires trained technicians to operate. In the event that your cat should need a CT, we can refer you to a specialist who can provide this service.